In some vehicles with diesel-cycle engines a gaseous fuel is used in place of diesel fuel. In these applications, the gaseous fuel is typically stored in a liquefied state at a cryogenic temperature. As an example, the vehicle may have a cryogenic storage tank that stores liquefied natural gas (LNG). The cryogenic plumbing used to deliver the LNG from the cryogenic storage tank to the engine of the vehicle experiences thermal cycles ranging from ambient temperature to LNG temperatures. As the temperature approaches LNG temperatures thermal contraction of the cryogenic plumbing occurs. In order to accommodate for the thermal contraction, conventional LNG plumbing systems employ various techniques such as using flexible hoses, bellows, and bends in the plumbing, to name a few examples. These traditional techniques help reduce stresses, caused from the thermal contraction, on the rigid support systems for the LNG plumbing. While effective, such support systems for the LNG plumbing, however, do not accommodate for the vertical and horizontal shock loads created during movement of the vehicle.
Although the various techniques of using flexible hoses, bellows, and bends in the plumbing help to reduce stresses in traditional LNG plumbing systems, these techniques commonly occupy a substantial amount of space. As such, these traditional techniques are non-ideal for space-limited vehicles. Additionally, such traditional techniques are also non-ideal for cryogenic plumbing systems that utilize high-pressure direct-injection (HPDI) systems, which require rigid plumbing.
U.S. Pat. No. 7,775,391 (the '391 patent) discloses a container for holding a cryogenic fuel. While the '391 patent teaches a straight conduit portion of the plumbing, it fails to teach the straight conduit portion of the plumbing in relation to being supported on the exterior of the container to accommodate for vertical shock loads and thermal contraction of the plumbing.